Supercooling system

ABSTRACT

The present invention relates to a supercooling system which can supply heat to a stored object or generate heat according to a sensed temperature to maintain the stored object in a supercooled state. The supercooling system includes a cooling apparatus including a storing unit storing a stored object, a cooling means cooling the storing unit, and a main control unit receiving external commercial power and controlling the cooling means to maintain the temperature in the storing unit at a temperature below the maximum ice crystal formation zone, and a supercooling apparatus including an independent storage room having a storing space therein to receive a storing container containing a liquid to be supercooled and mounted and cooled in the storing unit, a temperature sensing unit sensing the temperature of the independent storage room, a temperature control means mounted in the independent storage room and controlling the internal temperature such that a temperature of an upper portion of the storing space or the storing container is higher than a temperature of the maximum ice crystal formation zone and a temperature of a lower portion of the storing space or the storing container, and a sub-control unit controlling the temperature control means based on the sensed temperature from the temperature sensing unit to store the liquid in a supercooled state, maintaining the temperature control means in the off state when the temperature of the storing space or the storing container is equal to or higher than a preset temperature-control start temperature, and controlling the temperature control means in the on and off states when the temperature of the storing space or the storing container storage sensing preset temperature-control start temperature.

TECHNICAL FIELD

The present invention relates to a supercooling system, and, moreparticularly, to a supercooling system and method which can supply heatto a stored object or generate heat according to a sensed temperature tomaintain the stored or stored object in a supercooled state.

BACKGROUND ART

Supercooling means the phenomenon that a molten object or a solid is notchanged although it is cooled to a temperature below the phasetransition temperature in an equilibrium state. A material has a stablestate at every temperature. If the temperature is slowly changed, theconstituent elements of the material can follow the temperature changes,maintaining the stable state at each temperature. However, if thetemperature is suddenly changed, since the constituent elements cannotbe changed to the stable state at each temperature, the constituentelements maintain a stable state of the initial temperature, or some ofthe constituent elements fail to be changed to a state of the finaltemperature.

For example, when water is slowly cooled, it is not temporarily frozenat a temperature below 0° C. However, when water enters a supercooledstate, it has a kind of quasi-stable state. As this unstable equilibriumstate is easily broken even by slight stimulation, water tends to moveto a more stable state. That is, if a small piece of material is putinto the supercooled liquid, or if the liquid is suddenly shaken, theliquid starts to be frozen at once such that its temperature reaches thefreezing point, and maintains a stable equilibrium state at thistemperature.

In general, an electrostatic atmosphere is made in a refrigerator andmeat and fish are thawed in the refrigerator at a minus temperature. Inaddition to the meat and fish, fruit is kept fresh in the refrigerator.

This technology uses a supercooling phenomenon. The supercoolingphenomenon indicates the phenomenon that a molten object or a solid isnot changed although it is cooled to a temperature below the phasetransition temperature in an equilibrium state. This technology includesKorean Patent Publication No. 2000-0011081 titled “Electrostatic fieldprocessing method, electrostatic field processing apparatus, andelectrodes therefor”.

FIG. 1 is a view of an example of a conventional thawing andfreshness-keeping apparatus. A keeping-cool room 1 is composed of athermal insulator 2 and an outer wall 5. A mechanism (not shown)controlling a temperature inside the room 1 is installed therein. Ametal shelf 7 installed in the room 1 has a two-layer structure. Targetobjects to be thawed or freshness-kept and ripened such as vegetables,meat and marine products are loaded on the respective layers. The metalshelf 7 is insulated from the bottom of the room 1 by an insulator 9. Inaddition, since a high voltage generator 3 can generate 0 to 5000 V ofDC and AC voltages, an insulation plate 2 a such as vinyl chloride, etc.is covered on the inside of the thermal insulator 2. A high-voltagecable 4 outputting the voltage of the high voltage generator 3 isconnected to the metal shelf 7 after passing through the outer wall 5and the thermal insulator 2.

When a user opens a door installed at the front of the keeping-cool room1, a safety switch 13 (see FIG. 2) is turned off to intercept the outputof the high voltage generator 3.

FIG. 2 is a circuit configuration view of the high voltage generator 3.100 V of AC is supplied to a primary side of a voltage regulationtransformer 15. Reference numeral 11 represents a power lamp and 19 aworking state lamp. When the door 6 is closed and the safety switch 13is on, a relay 14 is operated. This state is displayed by a relayoperation lamp 12. Relay contact points 14 a, 14 b and 14 c are closedby the operation of the relay 14, and 100 V of AC is applied to theprimary side of the voltage regulation transformer 15.

The applied voltage is regulated by a regulation knob 15 a on asecondary side of the voltage regulation transformer 15, and theregulated voltage value is displayed on a voltmeter. The regulation knob15 a is connected to a primary side of a boosting transformer 17 on thesecondary side of the voltage regulation transformer 15. The boostingtransformer 17 boosts the voltage at a ratio of 1:50. For example, when60 V of voltage is applied, it is boosted to 3000 V.

One end O₁ of the output of the secondary side of the boostingtransformer 17 is connected to the metal shelf 7 insulated from thekeeping-cool room 1 through the high-voltage cable 4, and the other endO₂ of the output is grounded. Moreover, since the outer wall 5 isgrounded, if the user touches the outer wall 5 of the keeping-cool room1, he/she does not get an electric shock. Further, in FIG. 1, when themetal shelf 7 is exposed in the room 1, it should be maintained in aninsulated state in the room 1. Thus, the metal shelf 7 needs to beseparated from the wall of the room 1 (the air performs an insulationfunction). Furthermore, if a target object 8 is protruded from the metalshelf 7 and brought into contact with the wall of the room 1, thecurrent flows to the ground through the wall of the room 1. Therefore,the insulation plate 2 a is attached to the inner wall to prevent dropof the applied voltage. Still furthermore, when the metal shelf 7 iscovered with vinyl chloride without being exposed in the room 1, anelectric field atmosphere is produced in the entire room 1.

In the prior art, an electric field or a magnetic field is applied tothe stored object to be cooled, such that the stored object enters asupercooled state. Accordingly, a complicated apparatus for producingthe electric field or the magnetic field should be provided to keep thestored object in the supercooled state, and the power consumption isincreased during the production of the electric field or the magneticfield. Additionally, the apparatus for producing the electric field orthe magnetic field should further include a safety device (e.g., anelectric or magnetic field shielding structure, an interception device,etc.) for protecting the user from high power, when producing orintercepting the electric field or the magnetic field.

DISCLOSURE Technical Problem

An object of the present invention is to provide a supercooling systemand method which can reliably prevent the formation of ice crystalnucleuses in a stored object of a supercooled state.

Another object of the present invention is to provide a supercoolingsystem and method which can prevent the formation of ice crystalnucleuses and easily adjust a supercooling temperature of a storedobject.

A further object of the present invention is to provide a supercoolingsystem which can maintain a stored object in a supercooled state only bythe power supply in a space where only the cooling is performed.

A still further object of the present invention is to provide asupercooling system which can maintain a desired supercooled state bypreventing the heat exchange between an upper portion and a lowerportion of a storing space.

A still further object of the present invention is to provide asupercooling system and method which can supply or generate heataccording to the temperature of an upper portion and a lower portion ofa storing space.

A still further object of the present invention is to provide asupercooling system and method which can circulate the air in a storingspace by forcible convection.

A still further object of the present invention is to provide asupercooling system and method which can actively control the operationof a fan according to the opening and closing of a storing unit door andthe operation of a heat source supply unit.

Technical Solution

According to an aspect of the present invention, there is provided asupercooling system, including: a cooling apparatus including a storingunit storing a stored object, a cooling means cooling the storing unit,and a main control unit receiving external commercial power andcontrolling the cooling means to maintain the temperature in the storingunit at a temperature below the maximum ice crystal formation zone; anda supercooling apparatus including an independent storage room having astoring space therein to receive a storing container containing a liquidto be supercooled and mounted and cooled in the storing unit, atemperature sensing unit sensing the temperature of the independentstorage room, a temperature control means mounted in the independentstorage room and controlling the internal temperature such that atemperature of an upper portion of the storing space or the storingcontainer is higher than a temperature of the maximum ice crystalformation zone and a temperature of a lower portion of the storing spaceor the storing container, and a sub-control unit controlling thetemperature control means based on the sensed temperature from thetemperature sensing unit to store the liquid in a supercooled state,maintaining the temperature control means in the off state when thetemperature of the storing space or the storing container is equal to orhigher than a preset temperature-control start temperature, andcontrolling the temperature control means in the on and off states whenthe temperature of the storing space or the storing container is lowerthan the preset temperature-control start temperature.

In addition, a boundary film is provided to limit the air and heatexchange between the upper and lower portions of the storing space, andat least a part of the storing container passes through the boundaryfilm, so that the storing container is located in the upper and lowerportions of the storing space.

Moreover, the temperature control means includes a heat source supplyunit supplying or generating heat in the independent storage room.

Furthermore, the heat source supply unit includes an upper heat sourcesupply unit installed in the upper portion of the storing space and alower heat source supply unit installed in the lower portion of thestoring space.

Still furthermore, the temperature sensing unit is installed in at leastone of the upper and lower portions of the storing space.

Still furthermore, the control unit independently controls the heatsource supply unit based on the temperature of a temperature sensorinstalled in the same space of the storing space.

Still furthermore, the control unit compares the temperature of thelower portion of the storing space or the stored object with the presettemperature-control start temperature to control the temperature controlmeans.

Still furthermore, the control unit compares an upper sensed temperatureand a lower sensed temperature sensed by the temperature sensing unitwith a first upper reference temperature and a first lower referencetemperature, respectively, when the temperature of the lower portion ofthe storing space or the stored object is lower than the presettemperature-control start temperature, and controls the upper heatsource supply unit and the lower heat source supply unit in the on statewhen the upper sensed temperature and the lower sensed temperature aresmaller than the first upper reference temperature and the first lowerreference temperature, respectively.

Still furthermore, the first upper reference temperature and the firstlower reference temperature are smaller than an upper controltemperature and a lower control temperature by a given value,respectively.

Still furthermore, the control unit compares the upper sensedtemperature and the lower sensed temperature sensed by the temperaturesensing unit with a second upper reference temperature and a secondlower reference temperature, respectively, when the temperature of thelower portion of the storing space or the stored object is lower thanthe preset temperature-control start temperature, and controls the upperheat source supply unit and the lower heat source supply unit in the offstate when the upper sensed temperature and the lower sensed temperatureare larger than the second upper reference temperature and the secondlower reference temperature, respectively. Still furthermore, the secondupper reference temperature and the second lower reference temperatureare larger than a upper control temperature and a lower controltemperature by a given value, respectively.

Still furthermore, the control unit maintains the previous on or offstate when the temperature of the lower portion of the storing space orthe stored object is lower than the preset temperature-control starttemperature and when the upper sensed temperature and the lower sensedtemperature sensed by the temperature sensing unit exist between thefirst upper reference temperature and the second upper referencetemperature and between the first lower reference temperature and thesecond lower reference temperature, respectively.

Still furthermore, the supercooling apparatus includes a fan elementcirculating the air in the lower portion of the storing space byforcible convection.

Still furthermore, the cooling apparatus includes a storing unit dooropening and closing the storing unit, and the control unit maintains thefan element in the off state when the storing unit door is opened andcontrols the fan element in the on or off state when the storing unitdoor is closed.

Still furthermore, the control unit controls the fan element in the onstate when the lower sensed temperature is higher than a fan operationreference temperature.

Still furthermore, when the lower sensed temperature is equal to orlower than the fan operation reference temperature, if at least one ofthe upper heat source supply unit and the lower heat source supply unitis in the on state, the control unit controls the fan element in the onstate.

According to another aspect of the present invention, there is provideda supercooling method for a supercooling system including a coolingapparatus cooling a storing unit storing a stored object to atemperature below the maximum ice crystal formation zone, and asupercooling apparatus installed in the storing unit, having a storingspace therein to receive a storing container containing a liquid, andmaintaining a temperature of an upper portion of the storing space orthe storing container to be higher than a temperature of the maximum icecrystal formation zone and a temperature of a lower portion of thestoring space or the storing container, the supercooling methodincluding: a cooling step of performing the cooling in the storing unitusing the cooling apparatus; and a heat source supply step ofselectively or simultaneously performing an upper heat source supplystep of supplying or generating heat in the upper portion of the storingspace or the storing container and a lower heat source supply step ofsupplying or generating heat in the lower portion of the storing spaceor the storing container using the supercooling apparatus, the coolingstep and the heat source supply step being performed regardless oforder.

Advantageous Effects

An embodiment of the present invention can stably maintain a storedobject in a supercooled state for an extended period of time by reliablypreventing the formation of ice crystal nucleuses in the stored objectof the supercooled state.

An embodiment of the present invention can maintain a supercooled statetemperature of a stored object in a desired region by preventing theformation of ice crystal nucleuses and easily adjusting the supercoolingtemperature of the stored object.

An embodiment of the present invention can achieve a simple structureand independent supercooling control for a stored object by maintainingthe stored object in a supercooled state only by the power supply in aspace where only the cooling is performed.

An embodiment of the present invention can maintain a desiredsupercooled state by preventing the heat exchange between an upperportion and a lower portion of a storing space, thus achieving stableand reliable storage.

An embodiment of the present invention can reliably maintain a storedobject in a supercooled state by supplying or generating heat accordingto the temperature of an upper portion and a lower portion of a storingspace.

An embodiment of the present invention can maintain the uniformtemperature distribution in a storing space by circulating the air inthe storing space by forcible convection, thereby stably maintaining astored object in a supercooled state.

An embodiment of the present invention can maintain a stored object in asupercooled state by actively controlling the operation of a fanaccording to the opening and closing of a storing unit door and theoperation of a heat source supply unit.

DESCRIPTION OF DRAWINGS

FIG. 1 is a view of an example of a conventional thawing andfreshness-keeping apparatus.

FIG. 2 is a circuit configuration view of a high voltage generator.

FIG. 3 is a view showing a process in which ice crystal nucleuses areformed in a liquid during the cooling.

FIG. 4 is a view showing a process of preventing the ice crystal nucleusformation, which is applied to a supercooling apparatus according to thepresent invention.

FIG. 5 is a schematic configuration view of the supercooling apparatusaccording to the present invention.

FIG. 6 is a graph showing a supercooled state of water in thesupercooling apparatus of FIG. 5.

FIG. 7 is a block diagram of a supercooling system adopting asupercooling apparatus according to the present invention.

FIG. 8 is a block diagram of the supercooling apparatus of FIG. 7.

FIG. 9 is a flowchart of an embodiment of a supercooling method for thesupercooling apparatus of FIG. 8.

FIG. 10 is a flowchart of another embodiment of the supercooling methodfor the supercooling apparatus of FIG. 8.

FIG. 11 is a detailed sectional view of the supercooling apparatus ofFIG. 5.

FIG. 12 is an exploded perspective view of the supercooling apparatus ofFIG. 5.

FIG. 13 is a perspective view of a refrigerator including a supercoolingapparatus according to the present invention.

MODE FOR INVENTION

Hereinafter, the present invention will be described in detail withreference to the exemplary embodiments and the accompanying drawings.

FIG. 3 is a view showing a process in which ice crystal nucleuses areformed in a liquid during the cooling. As illustrated in FIG. 3, acontainer C containing a liquid L (or a stored object) is cooled in astoring unit S with a cooling space therein.

For example, it is assumed that a cooling temperature of the coolingspace is lowered from a room temperature to a temperature below 0° C.(the phase transition temperature of water) or a temperature below thephase transition temperature of the liquid L. While the cooling iscarried out, it is intended to maintain a supercooled state of the wateror the liquid L (or the stored object) at a temperature below themaximum ice crystal formation zone (−1° C. to −7° C.) of the water inwhich the formation of ice crystals is maximized, or at a coolingtemperature below the maximum ice crystal formation zone of the liquidL.

The liquid L is evaporated during the cooling such that vapor W1 isintroduced into a gas Lg (or a space) in the container C. In a casewhere the container C is closed, the gas Lg may be supersaturated due tothe evaporated vapor W1.

When the cooling temperature reaches or exceeds a temperature of themaximum ice crystal formation zone of the liquid L, the vapor W1 formsice crystal nucleuses F1 in the gas Lg or ice crystal nucleuses F2 on aninner wall of the container C. Alternatively, the condensation occurs ina contact portion of the surface Ls of the liquid L and the inner wallof the container C (almost the same as the cooling temperature of thecooling space) such that the condensed liquid L may form ice crystalnucleuses F3 which are ice crystals.

For example, when the ice crystal nucleuses F1 in the gas Lg are loweredand infiltrated into the liquid L through the surface Ls of the liquidL, the liquid L is released from the supercooled state and caused to befrozen. That is, the supercooling of the liquid L is released.

Alternatively, as the ice crystal nucleuses F3 are brought into contactwith the surface Ls of the liquid L, the liquid L is released from thesupercooled state and caused to be frozen.

As described above, according to the process of forming the ice crystalnucleuses F1 to F3, when the liquid L is stored at a temperature belowits maximum ice crystal formation zone, the liquid L is released fromthe supercooled state due to the freezing of the vapor evaporated fromthe liquid L and existing on the surface Ls of the liquid L and thefreezing of the vapor on the inner wall of the container C adjacent tothe surface Ls of the liquid L.

FIG. 4 is a view showing a process of preventing the ice crystal nucleusformation, which is applied to a supercooling apparatus according to thepresent invention.

In FIG. 4, to prevent the freezing of the vapor W1 in the gas Lg, i.e.,to continuously maintain the vapor W1 state, energy is applied to atleast the gas Lg or the surface Ls of the liquid L so that thetemperature of the gas Lg or the surface Ls of the liquid L can behigher than a temperature of the maximum ice crystal formation zone ofthe liquid L, more preferably, the phase transition temperature of theliquid L. In addition, to prevent the freezing although the surface Lsof the liquid L is brought into contact with the inner wall of thecontainer C, the temperature of the surface Ls of the liquid L ismaintained higher than a temperature of the maximum ice crystalformation zone of the liquid L, more preferably, the phase transitiontemperature of the liquid L.

Accordingly, the liquid L in the container C maintains the supercooledstate at a temperature below its phase transition temperature or atemperature below its maximum ice crystal formation zone.

Moreover, when the cooling temperature in the storing unit S is aconsiderably low temperature, e.g., −20° C., although energy is appliedto an upper portion of the container C, the liquid L which is the storedobject may not be able to maintain the supercooled state. There is aneed that energy should be applied to a lower portion of the container Cto some extent. When the energy applied to the upper portion of thecontainer C is relatively larger than the energy applied to the lowerportion of the container C, the temperature of the upper portion of thecontainer C can be maintained higher than the phase transitiontemperature or a temperature of the maximum ice crystal formation zone.Further, the temperature of the liquid L in the supercooled state can beadjusted by the energy applied to the lower portion of the container Cand the energy applied to the upper portion of the container C.

The liquid L has been described as an example with reference to FIGS. 3and 4. In the case of a stored object containing a liquid, when theliquid in the stored object is continuously supercooled, the storedobject can be kept fresh for an extended period of time. The storedobject can be maintained in a supercooled state at a temperature belowthe phase transition temperature via the above process. Here, the storedobject may include meat, vegetable, fruit and other food as well as theliquid.

Furthermore, the energy used in the present invention may be thermalenergy, electric or magnetic energy, ultrasonic-wave energy, lightenergy, and so on.

FIG. 5 is a schematic configuration view of the supercooling apparatusaccording to the present invention.

The supercooling apparatus of FIG. 5 includes a case Sr mounted in thestoring unit S in which the cooling is performed and having a storingspace therein, a heat generation coil H1 mounted on the inside of thetop surface of the case Sr and generating heat, a temperature sensor C1sensing a temperature of an upper portion of the storing space, a heatgeneration coil H2 mounted on the inside of the bottom surface of thecase Sr and generating heat, and a temperature sensor C2 sensing atemperature of a lower portion of the storing space or a temperature ofa stored object P.

The supercooling apparatus is installed in the storing unit S. While thecooling is performed, the temperature sensors C1 and C2 sense thetemperature and the heat generation coils H1 and H2 are turned on tosupply heat from the upper and lower portions of the storing space tothe storing space. The heat supply quantity is adjusted to control thetemperature of the upper portion of the storing space (or the air on thestored object P) to be higher than a temperature of the maximum icecrystal formation zone, more preferably, the phase transitiontemperature.

Particularly, a boundary film Br is formed in the case Sr to separatethe upper and lower portions of the storing space and prevent the heatexchange between the upper and lower portions thereof. The boundary filmBr includes a hole Hr through which a top end portion of a container Crcontaining a liquid P is located in the upper portion of the storingspace. The portion of the boundary film Br around the hole Hr is made ofan elastic material to minimize the air flow, particularly, the heatflow between the upper and lower portions of the storing space. Theupper portion of the container Cr passes through the boundary film Brand is located in the upper portion of the storing space, and the lowerportion of the container Cr is located in the lower portion of thestoring space. The boundary film Br makes it easy to maintain the upperand lower portions of the storing space or the upper and lower portionsof the container Cr at a desired temperature.

In addition, a fan element Fr is provided in the lower storing space ofthe case Sr to circulate the air and heat in the lower portion byforcible convection. Accordingly, the heat supplied by the heatgeneration coil H2 can be uniformly transferred to the lower storingspace and the stored object.

The positions of the heat generation coils H1 and H2 in FIG. 5 areappropriately determined to supply the heat (or energy) to the storedobject P and the storing space. The heat generation coils H1 and H2 maybe inserted into the side surfaces of the case Sr.

FIG. 6 is a graph showing the supercooled state of water in thesupercooling apparatus of FIG. 5. The graph of FIG. 6 is a temperaturegraph when the liquid L is water and the principle of FIGS. 4 and 5 isapplied thereto.

As illustrated in FIG. 6, a line I represents a curve of the coolingtemperature of the cooling space, a line II represents a curve of thetemperature of the gas Lg (air) on the surface of the water in thecontainer C or the case Sr (or the temperature of the upper portion ofthe container C or the case Sr), and a line III represents a curve ofthe temperature of the lower portion of the container C, the case Sr orthe container Cr. A temperature of an outer surface of the container C,the case Sr or the container Cr is substantially identical to thetemperature of the water or liquid in the container C, the case Sr orthe container Cr.

As shown, in a case where the cooling temperature is maintained at about−19° C. to −20° C. (see the line I), when the temperature of the gas Lgon the surface of the water in the container C is maintained at about 4°C. to 6° C. which is higher than a temperature of the maximum icecrystal formation zone of the water, the temperature of the water in thecontainer C is maintained at about −11° C. which is lower than atemperature of the maximum ice crystal formation zone of the water, butthe water is stably maintained in a supercooled state which is a liquidstate for an extended period of time. Here, the heat generation coils H1and H2 supply heat.

Additionally, in FIG. 6, energy is applied to the surface of the wateror the gas Lg on the surface of the water before the temperature of thewater reaches a temperature of the maximum ice crystal formation zone,more preferably, the phase transition temperature due to the cooling.Thus, the water stably enters and maintains the supercooled state. FIG.7 is a block diagram of a supercooling system adopting a supercoolingapparatus according to the present invention, and FIG. 8 is a blockdiagram of the supercooling apparatus of FIG. 7.

The supercooling system includes a cooling apparatus 100, and asupercooling apparatus 200 mounted in and cooled by the coolingapparatus 100.

The cooling apparatus 100, which is provided with a storing unit storinga stored object, includes a cooling cycle (i.e., cooling means) 110cooling the storing unit, an input unit 120 receiving the input of asetting command or the like from a user, a display unit 130 displaying atemperature state or the like of the cooling apparatus 100, and a maincontrol unit 140 receiving external commercial power (or another power)and controlling the cooling cycle 110 to maintain the temperature in thestoring unit at a temperature below at least the maximum ice crystalformation zone. Here, like a general refrigerator or freezer, thestoring unit includes a storing space storing the stored object and astoring unit door opening and closing the storing space, so that theuser can put the stored object into the storing unit and take the storedobject out of the storing unit. The cooling cycle 110 is divided intoindirect-cooling type and direct-cooling type according to methods forcooling the stored object.

The indirect-cooling type cooling cycle includes a compressorcompressing the refrigerant, an evaporator producing the cool air tocool a storing space or a stored object, a fan making the forcible flowof the produced cool air, an inlet duct introducing the cool air intothe storing space, and a discharge duct inducing the cool air passingthrough the storing space to the evaporator. In addition, theindirect-cooling type cooling cycle may include a condenser, a dryer, anexpansion device, etc.

The direct-cooling type cooling cycle includes a compressor compressingthe refrigerant, and an evaporator provided in a case defining a storingspace to be adjacent to the inner surface of the case and evaporatingthe refrigerant. Here, the direct-cooling type cooling cycle includes acondenser, an expansion valve, etc.

The input unit, which receives the input of temperature setting of thestoring unit, an operation command of the supercooling apparatus 200,function setting of a dispenser, and so on from the user, may beprovided as, e.g., push buttons, a keyboard or a touch pad. For example,the operation commands of the supercooling apparatus 200 may include afreezing command, a thin-ice command, a supercooling command, etc.

The display unit 130 may display an operation basically performed by thecooling apparatus 100, e.g. the temperature of the storing unit, thecooling temperature, the operation state of the supercooling apparatus200, etc. The display unit 130 may be implemented as an LCD display, anLED display, etc.

In this embodiment, the main control unit 140 includes a power unit 142receiving commercial power (e.g., 220 V, 100 V, 230 V, etc.) andrectifying, smoothing and transforming the commercial power intooperating power (e.g., 5 V, 12 V, etc.) necessary for the coolingapparatus 100 and the supercooling apparatus 200. The power unit 142 maybe included in the main control unit 140 or provided as a separateelement. The power unit 142 is connected to the supercooling apparatus200 through a power line PL and supplies the necessary operating powerto the supercooling apparatus 200.

The main control unit 140 includes a microcomputer 144 controlling thecooling cycle 110, the input unit 120 and the display unit 130 to enablethe cooling apparatus 100 to perform the cooling operation andmaintaining the inside of the storing unit at a temperature below atleast the maximum ice crystal formation zone. The main control unit 140includes a memory (not shown) storing necessary data.

The main control unit 140 (particularly, the microcomputer 144) may beconnected to the supercooling apparatus 200 through a data line DL. Themain control unit 140 may receive data (e.g., the current operationstate of the supercooling apparatus 200) from the supercooling apparatus200 through the data line DL, and store the data or display the data onthe display unit 130. The data line DL may be selectively provided.

The microcomputer 144 controls the temperature in the storing unitaccording to the temperature setting from the input unit 120, andmaintains the inside of the storing unit at a temperature below at leastthe maximum ice crystal formation zone so that the supercoolingapparatus 200 can independently perform the supercooling control, etc.As illustrated in FIG. 8, the supercooling apparatus 200, which isprovided with an independent storage room having a storing space thereinto receive an object, like the case of FIG. 5, and mounted and cooled inthe storing unit, includes a heat source supply unit 210 supplying heatto the storing space or generating heat in the storing space, atemperature sensing unit 220 sensing the temperature of the storingspace or the stored object, an input unit 230 receiving the input of acommand from the user, a display unit 240 displaying a state of thestoring space or the stored object or an operation of the supercoolingapparatus 200, and a sub-control unit 280 controlling the heat sourcesupply unit 210, which is a temperature control means, based on thesensed temperature from the temperature sensing unit 220 so that thestored object in the independent storage room can be stored at least ina supercooled state.

The independent storage room includes a boundary portion separating theupper and lower portions of the container Cr and preventing or limitingthe air and heat exchange therebetween as in FIG. 5.

The supercooling apparatus 200 is operated by the operating powerapplied from the main control unit 140. The wiring for power supply (thewiring connected to the power line PL) is connected to the entirepower-needing components. This configuration has been publicly known toa person of ordinary skill in the art, and thus its description will beomitted.

The heat source supply unit 210 corresponds to a temperature controlmeans which controls the temperature in the storing space to maintainthe temperature for each of the supercooled-state control, the thin-icecontrol and the freezing control. The heat source supply unit 210, whichis a means for applying energy to the storing space, may produce thermalenergy, electric or magnetic energy, ultrasonic-wave energy, lightenergy, microwave energy, etc. and apply such energy to the storingspace. Moreover, the heat source supply unit 210 may supply energy tothaw the stored object, when it is frozen.

The heat source supply unit 210 is composed of a plurality of sub-heatsource supply units and mounted on the upper or lower portion or theside surface of the storing space to supply energy to the storing space.In this embodiment, the heat source supply unit 210 includes an upperheat source supply unit 210 a (e.g., the one corresponding to the heatgeneration coil H1 of FIG. 5) formed in the upper space of theindependent storage room which is the upper side of the storing space,and a lower heat source supply unit 210 b (e.g., the one correspondingto the heat generation coil H2 of FIG. 5) formed in the lower space ofthe independent storage room which is the lower side of the storingspace. The upper heat source supply unit 210 a and the lower heat sourcesupply unit 210 b may be independently or integrally controlled by thesub-control unit 280.

Further, the temperature sensing unit 220, which senses the temperatureof the storing space or the temperature of the stored object,corresponds to a sensor provided on a sidewall of the storing space tosense the temperature of the air in the storing space or provided inproximity or contact with the stored object to accurately sense thetemperature of the stored object. The temperature sensing unit 220applies a change value of a current value, a voltage value or aresistance value corresponding to the temperature to the sub-controlunit 280. The temperature sensing unit 220 senses a sudden rise in thetemperature of the stored object or the storing space during the phasetransition of the stored object and enables the sub-control unit 280 torecognize the release of the supercooled state of the stored object.

In this embodiment, the temperature sensing unit 220 may be composed ofan upper sensing unit 220 a (e.g., the one corresponding to thetemperature sensor C1 of FIG. 5) formed in the upper side of theindependent storage room which is the upper side of the storing space,and a lower sensing unit 220 b (e.g., the one corresponding to thetemperature sensor C2 of FIG. 5) formed in the lower side of theindependent storage room which is the lower side of the storing space.The upper sensing unit 220 a and the lower sensing unit 220 b aremounted on or adjacent to the surfaces having the upper heat sourcesupply unit 210 a and the lower heat source supply unit 210 b thereon.The sub-control unit 280 may control the heat source supply unit 210 toperform at least the supercooling control according to the sensedtemperature from the temperature sensing unit 220. Particularly, thesub-control unit 280 may control the upper heat source supply unit 210 aaccording to the sensed temperature from the upper sensing unit 220 aand the lower heat source supply unit 210 b according to the sensedtemperature from the lower sensing unit 220 b, respectively.

The input unit 230, which enables the user to select an on/off switchfunction of the supercooling apparatus 200 and a supercooling controlcommand, may be provided as, e.g., push buttons, a keyboard or a touchpad.

The display unit 240, which displays the on/off state of thesupercooling apparatus 200 and the current control thereof (e.g., thesupercooling control), may be provided as an LCD display, an LEDdisplay, etc.

As described above, the sub-control unit 280 may control the heat sourcesupply unit 210 according to the sensed temperature from the temperaturesensing unit 220, thereby independently performing the supercoolingcontrol with respect to the main control unit 140 and the coolingapparatus 100. For this independent control, the sub-control unit 280may include a memory storing a control algorithm, etc.

In the supercooling control, the temperature of the stored object rangesfrom, e.g., −3° C. to −4° C. and the stored object is stored in thesupercooled state. The control which senses the freezing of the storedobject of the supercooled state by the phenomenon that the temperatureof the stored object suddenly rises from, e.g., −4° C. is furtherperformed during the supercooling control. Furthermore, the controlwhich performs the thawing through the operation of the heat sourcesupply unit 210 and resumes the cooling after the completion of thethawing is performed in the release of the supercooled state.

The sub-control unit 280 may intercept the power supply to therespective elements according to the on/off switch input of thesupercooling apparatus 200 from the input unit 230, thereby preventingtheir operation.

The input unit 230 further has a function of acquiring a thawingcommand, and the sub-control unit 280 operates the heat source supplyunit 210 to apply energy (particularly, heat energy) to thaw the storedobject according to the thawing command from the input unit 230.

A fan driving unit 250 is an element driving a fan element Fr formed inthe lower space of the storing space in the independent storage room.The driving of the fan element Fr makes the temperature distribution inthe lower space of the storing space uniform. Due to the uniformtemperature distribution, the stored object can rapidly enter and stablymaintain the supercooled state.

A door sensing unit 260 is a component sensing the opening and closingof a door opening and closing the storing unit of the cooling apparatus100. Like a door opening/closing sensing means of a generalrefrigerator, the door sensing unit 260 may be a switch turned on/off bythe storing unit door. Alternatively, the sub-control unit 280 mayreceive the opening and closing information of the door from the maincontrol unit 140 through a data line DL and check the opening andclosing of the storing unit door.

FIG. 9 is a flowchart of an embodiment of a supercooling method for thesupercooling apparatus of FIG. 8.

At step S91, the cooling apparatus 100 performs the cooling in thestoring unit, which cools the supercooling apparatus 200 (particularly,the independent storage room) mounted in the storing unit.

At step S93, the sub-control unit 280 determines whether a temperaturesensed by and acquired from the temperature sensing unit 220 is lowerthan a temperature-control start temperature Ts. In this step, thesub-control unit 280 compares a lower sensed temperature Tl sensed bythe lower sensing unit 220 b with the temperature-control starttemperature Ts. As the object is mostly received in the lower portion ofthe container, the lower sensed temperature Tl more directly reflectsthe temperature of the stored object. Therefore, the reason for usingthe lower sensed temperature Tl for the comparison is to accuratelyrapidly sense the state (temperature) of the stored object. Here, forexample, when the temperature is higher than the phase transitiontemperature, the supercooling of the stored object is not released, andthus the temperature control is not required. However, when thetemperature is equal to or lower than the phase transition temperatureor enters the maximum ice crystal formation zone, the release of thesupercooled state becomes an important issue. The temperature-controlstart temperature Ts corresponds to a temperature at which thetemperature control is required to maintain the storing space and thestored object in the supercooled state. For example, thetemperature-control start temperature Ts may be 0° C. which is the phasetransition temperature. If the lower sensed temperature Tl is lower thanthe temperature-control start temperature Ts, the sub-control unit 280goes to step S95, and if not, the sub-control unit 280 is in the standbystate.

At step S95, the sub-control unit 280 compares an upper sensedtemperature Tu sensed by the upper sensing unit 220 a with a first upperreference temperature (=upper control temperature Tuc+constanttemperature Ca). The first upper reference temperature is a temperaturehigher than the upper control temperature Tuc set by the sub-controlunit 280 or the user through the input unit 230 by the constanttemperature Ca. Here, the constant temperature Ca has a positivetemperature value. For example, the upper control temperature Tuc is +4°C. and the constant temperature Ca is 0.4° C. Although the upper sensedtemperature Tu is not the same as the upper control temperature Tuc buthas a margin equivalent to the constant temperature Ca, the supercooledstate is not released, and thus the constant temperature Ca is used. Ifthe upper sensed temperature Tu is higher than the first upper referencetemperature, the sub-control unit 280 goes to step S97, and if not, thesub-control unit 280 goes to step S99.

At step S97, since the temperature of the upper portion of the storingspace or the container is higher than the first upper referencetemperature, the sub-control unit 280 turns off the upper heat sourcesupply unit 210 a.

At step S99, the sub-control unit 280 compares the upper sensedtemperature Tu with a second upper reference temperature (=upper controltemperature Tuc−constant temperature Cb). The second upper referencetemperature is a temperature lower than the upper control temperatureTuc set by the sub-control unit 280 or the user through the input unit230 by the constant temperature Cb. Here, the constant temperature Cbhas a positive temperature value. For example, the upper controltemperature Tuc is +4° C. and the constant temperature Cb is 0.4° C.Although the upper sensed temperature Tu is not the same as the uppercontrol temperature Tuc but has a margin equivalent to the constanttemperature Cb, the supercooled state is not released, and thus theconstant temperature Cb is used. If the upper sensed temperature Tu islower than the second upper reference temperature, the sub-control unit280 goes to step S101. If not, the sub-control unit 280 goes to stepS103 to maintain the current operation of the upper heat source supplyunit 210 a (the ongoing on/off control).

At step S101, the sub-control unit 280 turns on the upper heat sourcesupply unit 210 a to supply or generate heat in the upper portion of thestoring space.

The sub-control unit 280 maintains the upper sensed temperature Tubetween (upper control temperature Tuc−constant temperature Cb) and(upper control temperature Tuc+constant temperature Ca) through thesteps of S95 to S101.

At step S103, the sub-control unit 280 compares the lower sensedtemperature Tl with a first lower reference temperature (=lower controltemperature Tlc+constant temperature Cc). The first lower referencetemperature is a temperature higher than the lower control temperatureTlc set by the sub-control unit 280 or the user through the input unit230 by the constant temperature Cc. Here, the constant temperature Cchas a positive temperature value. The lower control temperature Tlc is−8° C. and the constant temperature Cc is 0.4° C. Although the lowersensed temperature Tl is not the same as the lower control temperatureTlc but has a margin equivalent to the constant temperature Cc, thesupercooled state is not released, and thus the constant temperature Ccis used. If the lower sensed temperature Tl is higher than the firstlower reference temperature, the sub-control unit 280 goes to step S105,and if not, the sub-control unit 280 goes to step S107.

At step S105, the sub-control unit 280 controls the lower heat sourcesupply unit 210 a in the off state.

At step S107, the sub-control unit 280 compares the lower sensedtemperature Tl with a second lower reference temperature (=lower controltemperature Tlc−constant temperature Cd). The second lower referencetemperature is a temperature lower than the lower control temperatureTlc set by the sub-control unit 280 or the user through the input unit230 by the constant temperature Cd. Here, the constant temperature Cdhas a positive temperature value. The lower control temperature Tlc is−8° C. and the constant temperature Cd is 0.4° C. Although the lowersensed temperature Tl is not the same as the lower control temperatureTlc but has a margin equivalent to the constant temperature Cd, thesupercooled state is not released, and thus the constant temperature Cdis used. If the lower sensed temperature Tl is lower than the secondlower reference temperature, the sub-control unit 280 goes to step S109.If not, the sub-control unit 280 goes to step S91 to maintain thecurrent operation of the lower heat source supply unit 210 b (theongoing on/off control).

The sub-control unit 280 maintains the lower sensed temperature Tlbetween (lower control temperature Tlc−constant temperature Cd) and(lower control temperature Tlc+constant temperature Cc) through thesteps of S103 to S109.

The above-described steps S93 to S101 and S103 to S109 may be performedin the reversed order or independently at the same time. That is, theupper heat source supply unit 210 a and the lower heat source supplyunit 210 b can be independently controlled by the sub-control unit 280.In addition, the cooling of step S91, the steps S93 to S101, and thesteps S103 to S109 may be performed regardless of order. That is, thesesteps may be performed in the reversed order or independently at thesame time.

FIG. 10 is a flowchart of another embodiment of the supercooling methodfor the supercooling apparatus of FIG. 8.

At step S121, the sub-control unit 280 determines whether the storingunit door is currently in the closed state. If the storing unit door isin the closed state, the sub-control unit 280 goes to step S125, and ifnot, the sub-control unit 280 goes to step S123.

At step S123, since the storing unit door is in the open state, thesub-control unit 280 stops the driving of the fan element Fr to preventthe noise of the fan element Fr from being transferred to the outside orminimize the influence of the outdoor air (temperature) exerted on thestoring space.

At step S125, the sub-control unit 280 compares a lower sensedtemperature Tl with a first fan operation reference temperature (=lowercontrol temperature Tlc+constant temperature Ce). Here, the constanttemperature Ce has a positive temperature value. For example, theconstant temperature Ce is +0.4° C. If the lower sensed temperature

Tl is higher than the first fan operation reference temperature, thesub-control unit 280 goes to step S127, and if not, the sub-control unit280 goes to step S129.

At step S127, the sub-control unit 280 drives the fan element Fr to makethe air and heat smoothly flow in the lower space.

At step S129, the sub-control unit 280 determines whether either theupper heat source supply unit 210 a or the lower heat source supply unit210 b is operated in the on state. If any one heat source supply unit210 is in the on state, the sub-control unit 280 goes to step S127 tomake the supplied or generated heat smoothly flow in the lower space. Ifnot, the sub-control unit 280 goes to step S123 to control the fanelement Fr in the off state.

The supercooling method of FIG. 9 and the supercooling method of FIG. 10may be independently or simultaneously performed by the sub-control unit280.

FIG. 11 is a detailed sectional view of the supercooling apparatus ofFIG. 5, and FIG. 12 is an exploded perspective view of the supercoolingapparatus of FIG. 5. The supercooling apparatus (or independent storageroom) according to the present invention includes a casing 1100 definingan inner space storing a container and a door 1200 opening and closingthe casing 1100, and is installed in a cooling apparatus storing food ata temperature below 0° C. such as a freezing chamber of a refrigerator.The casing 1100, which separates the outer space, i.e., the space in thecooling apparatus where the supercooling apparatus is installed from theinner space in the supercooling apparatus, includes outer casings 1110and 1120 forming the external appearance of the supercooling apparatus.The outer casings 1110 and 1120 include a front outer casing 1110 and arear outer casing 1120. The front outer casing 1110 forms the externalappearance of the front and lower portions of the supercoolingapparatus, and the rear outer casing 1120 forms the external appearanceof the rear and upper portions of the supercooling apparatus. The casing1100 enables upper and lower portions of the container containing aliquid to be located and stored in different temperature regions. Morespecifically, the lower portion of the container is located in atemperature region (about −1° C. to −7° C.) of the maximum ice crystalformation zone, and the upper portion of the container is located in ahigher temperature region (about −1° C. to 2° C.) in which the icecrystals are not easy to form. For this purpose, the casing 1100includes a lower space 1100L having the temperature region (about −1° C.to −7° C.) of the maximum ice crystal formation zone, and an upper space1100U having the temperature region (about −1° C. to 2° C.) in which theice crystals are not easy to form. The upper space 1100U and the lowerspace 1100L are separated by a bulkhead 1140. The casing 1100 includesan inner casing 1130 defining the lower space 1100L with the bulkhead1140 and a cap casing 1150 defining the upper space 11000 with thebulkhead 1140.

A cooling fan 1170 is installed at the rear of the lower space 1100L sothat the liquid stored in the lower portion of the container located inthe lower space 1100L can rapidly reach the temperature region (about−1° C. to −7° C.) of the maximum ice crystal formation zone and have asupercooled state. In addition, a lower heater 1164 is provided toadjust the temperature of the lower space 1100L. An upper heater 1162 isinstalled around the cap casing 1150 so that the upper portion of thecontainer located in the upper space 11000 can be maintained in thetemperature region (about −1° C. to 2° C.) in which the ice crystals arenot easy to form. Moreover, a separation film 1142 made of an elasticmaterial is installed on the bulkhead 1140 to prevent the heat exchangefrom occurring between the upper space 11000 and the lower space 1100Lhaving different temperatures due to a forcible flow produced by thecooling fan 1170.

Meanwhile, a thermal insulator 1112 for insulating the lower space 1100Lfrom the outer space is provided in the lower portions of the outercasings 1110 and 1120, and a thermal insulator 1122 for insulating theupper space 1100U from the outer space is provided in the upper portionsof the outer casings 1110 and 1120. In addition, a power switch 1182, adisplay unit 1184 and the like are installed between the front outercasing 1110 and the thermal insulator 1122, and a control unit (notshown) and a control unit installation portion 1186 are installedbetween the rear outer casing 1120 and the thermal insulator 1122.

The door 1200 is installed on the front surface of the front outercasing 1110 to open and close the lower space 1100L. The door 1200includes a door window 1220 made of a transparent or semitransparentmaterial in a door casing 1210, a door frame 1230 fixed to the doorcasing 1210 and fixing the door window 1220 therewith, and a gasket 1240mounted at the rear of the door frame 1230 and sealing between the door1200 and the front outer casing 1110.

The supercooling apparatus of the present invention may be provided inthe refrigerator, particularly, in the freezing chamber of therefrigerator and installed in the freezing chamber door. As thesupercooling apparatus of the present invention has a shallow depth anda relatively large height and width compared to the depth, it may beinstalled in the freezing chamber door to occupy a minimum area in thestoring space of the freezing chamber.

FIG. 13 is a view of a refrigerator including a supercooling apparatusaccording to the present invention. The refrigerator 2000 is partitionedinto a freezing chamber 2100 and a refrigerating chamber 2200 providedwith a door, respectively. The supercooling apparatus 200 is provided insuch a manner that a casing 1100 is fixed to the freezing chamber door.The cool air in the freezing chamber 2100 is introduced into thesupercooling apparatus 200 installed in the door to cool a container anda liquid contained in the container.

In a state where the freezing chamber door is opened, if a cooling fan1170 and heaters 1162 and 1164 are operated, the air of room temperaturemay be circulated in the supercooling apparatus at a high speed andsuddenly raise the temperature of the liquid maintained in thesupercooled state. A sensor 1118 capable of sensing the opening of thefreezing chamber door may be installed around a rotating shaft of thefreezing chamber door or in the opposite side. The embodiment of FIG. 12shows a case in which the sensor 1118 is installed around the rotatingshaft, and the embodiment FIG. 13 shows a case in which the sensor 1118is installed in the opposite side to the rotating shaft in the door. Ifthe sensor 1118 is installed in the opposite side to the rotating shaftin the door, a user can easily press the sensor 1118 to operate thecooling fan 1170 and the heaters 1162 and 1164 in the same way as whenthe door is closed, so that the air of room temperature can becirculated in the supercooling apparatus by the convection. The positionof the sensor 1118 and the opening direction of the door 1200 may beoptionally changed. Meanwhile, the supercooling apparatus may beprovided to be detachable from the freezing chamber door. That is, whena coupling device composed of concave and convex parts is provided tothe outer casing 1100 and the freezing chamber door to fix thesupercooling apparatus, if the supercooling apparatus is necessary, itcan be attached to the inside of the freezing chamber door. On thecontrary, if the supercooling apparatus is not necessary, it can bedetached from the freezing chamber door, so that the space in thefreezing chamber door can be effectively used. In the meantime, when thesupercooling apparatus is provided in detachable type, a terminalcapable of transferring power should be provided between the freezingchamber door and the outer casing 1110.

According to another embodiment of the refrigerator including thesupercooling apparatus, although a supercooling apparatus is installedin a freezing chamber door, a user can take out a liquid stored in asupercooled state without opening the freezing chamber door. An openingportion is formed in the freezing chamber door, and a door 1200 of thesupercooling apparatus is formed in a position corresponding to theopening portion. Therefore, the door 1200 of the supercooling apparatuscan be opened through the opening portion. In this situation, it ispreferable to form a thermal insulator in the door 1200 of thesupercooling apparatus to prevent the heat exchange with the outer spacethrough the door 1200 of the supercooling apparatus. Alternatively, likefreezing chamber door, a door provided with a thermal insulator isformed on the opening portion of the freezing chamber door. Here, totake a container containing a supercooled liquid out of the supercoolingapparatus or put the container into the supercooling apparatus, the usershould open the door for opening and closing the opening portion, andthen open the door 1200 of the supercooling apparatus. If the door 1200of the supercooling apparatus and the door for opening and closing theopening portion formed in the freezing chamber door are separatelyformed, the thermal insulation effect is improved but the convenience inuse is reduced. On the contrary, if the door 1200 of the supercoolingapparatus includes the thermal insulator and opens and closes theopening portion of the freezing chamber door, the thermal insulationeffect is a little degraded. However, the user only needs to open onedoor to use the supercooling apparatus. If the door 1200 of thesupercooling apparatus and the door for opening and closing the openingportion of the freezing chamber door are separately formed, it ispreferable that a switch mounting portion having a switch installedthereon to turn on/off power of the supercooling apparatus and a displayunit displaying the state of the liquid stored in the supercoolingapparatus should be provided on the freezing chamber door or the doorfor opening and closing the opening portion of the freezing chamberdoor.

The present invention has been described in detail in connection withthe exemplary embodiments and the accompanying drawings. However, thescope of the present invention is not limited thereto but is defined bythe appended claims.

1. A supercooling system, comprising: a cooling apparatus including astoring unit storing a stored object, a cooling means cooling thestoring unit, and a main control unit receiving external commercialpower and controlling the cooling means to maintain the temperature inthe storing unit at a temperature below the maximum ice crystalformation zone; and a supercooling apparatus including an independentstorage room having a storing space therein to receive a storingcontainer containing a liquid to be supercooled and mounted and cooledin the storing unit, a temperature sensing unit sensing the temperatureof the independent storage room, a temperature control means mounted inthe independent storage room and controlling the internal temperaturesuch that a temperature of an upper portion of the storing space or thestoring container is higher than a temperature of the maximum icecrystal formation zone and a temperature of a lower portion of thestoring space or the storing container, and a sub-control unitcontrolling the temperature control means based on the sensedtemperature from the temperature sensing unit to store the liquid in asupercooled state, maintaining the temperature control means in the offstate when the temperature of the storing space or the storing containeris equal to or higher than a preset temperature-control starttemperature, and controlling the temperature control means in the on andoff states when the temperature of the storing space or the storingcontainer is lower than the preset temperature-control starttemperature.
 2. The supercooling system of claim 1, wherein a boundaryfilm is provided to limit the air and heat exchange between the upperand lower portions of the storing space, and at least a part of thestoring container passes through the boundary film, so that the storingcontainer is located in the upper and lower portions of the storingspace.
 3. The supercooling system of claim 2, wherein the temperaturecontrol means comprises a heat source supply unit supplying orgenerating heat in the independent storage room.
 4. The supercoolingsystem of claim 3, wherein the heat source supply unit comprises anupper heat source supply unit installed in the upper portion of thestoring space and a lower heat source supply unit installed in the lowerportion of the storing space.
 5. The supercooling system of claim 4,wherein the temperature sensing unit is installed in at least one of theupper and lower portions of the storing space.
 6. The supercoolingsystem of claim 5, wherein the control unit independently controls theheat source supply unit based on the temperature of a temperature sensorinstalled in the same space of the storing space.
 7. The supercoolingsystem of claim 6, wherein the control unit compares the temperature ofthe lower portion of the storing space or the stored object with thepreset temperature-control start temperature to control the temperaturecontrol means.
 8. The supercooling system of claim 7, wherein thecontrol unit compares an upper sensed temperature and a lower sensedtemperature sensed by the temperature sensing unit with a first upperreference temperature and a first lower reference temperature,respectively, when the temperature of the lower portion of the storingspace or the stored object is lower than the preset temperature-controlstart temperature, and controls the upper heat source supply unit andthe lower heat source supply unit in the on state when the upper sensedtemperature and the lower sensed temperature are smaller than the firstupper reference temperature and the first lower reference temperature,respectively.
 9. (canceled)
 10. The supercooling system of claim 7,wherein the control unit compares the upper sensed temperature and thelower sensed temperature sensed by the temperature sensing unit with asecond upper reference temperature and a second lower referencetemperature, respectively, when the temperature of the lower portion ofthe storing space or the stored object is lower than the presettemperature-control start temperature, and controls the upper heatsource supply unit and the lower heat source supply unit in the offstate when the upper sensed temperature and the lower sensed temperatureare larger than the second upper reference temperature and the secondlower reference temperature, respectively.
 11. (canceled)
 12. Thesupercooling system of claim 7, wherein the control unit maintains theprevious on or off state when the temperature of the lower portion ofthe storing space or the stored object is lower than the presettemperature-control start temperature and when the upper sensedtemperature and the lower sensed temperature sensed by the temperaturesensing unit exist between the first upper reference temperature and thesecond upper reference temperature and between the first lower referencetemperature and the second lower reference temperature, respectively.13. The supercooling system of claim 6, wherein the supercoolingapparatus comprises a fan element circulating the air in the lowerportion of the storing space by forcible convection.
 14. Thesupercooling system of claim 13, wherein the cooling apparatus comprisesa storing unit door opening and closing the storing unit, and thecontrol unit maintains the fan element in the off state when the storingunit door is opened and controls the fan element in the on or off statewhen the storing unit door is closed.
 15. The supercooling system ofclaim 13, wherein the control unit controls the fan element in the onstate when the lower sensed temperature is higher than a fan operationreference temperature, and when the lower sensed temperature is equal toor lower than the fan operation reference temperature, if at least oneof the upper heat source supply unit and the lower heat source supplyunit is in the on state, the control unit controls the fan element inthe on state.
 16. (canceled)
 17. A supercooling method for asupercooling system including a cooling apparatus cooling a storing unitstoring a stored object to a temperature below the maximum ice crystalformation zone, and a supercooling apparatus installed in the storingunit, having a storing space therein to receive a storing containercontaining a liquid, and maintaining a temperature of an upper portionof the storing space or the storing container to be higher than atemperature of the maximum ice crystal formation zone and a temperatureof a lower portion of the storing space or the storing container, thesupercooling method comprising: a cooling step of performing the coolingin the storing unit using the cooling apparatus; and a heat sourcesupply step of selectively or simultaneously performing an upper heatsource supply step of supplying or generating heat in the upper portionof the storing space or the storing container and a lower heat sourcesupply step of supplying or generating heat in the lower portion of thestoring space or the storing container using the supercooling apparatus,the cooling step and the heat source supply step being performedregardless of order.
 18. The supercooling method of claim 17, whereinthe supercooling method selectively or simultaneously performs an uppertemperature sensing step of sensing the temperature of the upper portionof the storing space or the storing container and a lower temperaturesensing step of sensing the temperature of the lower portion of thestoring space or the storing container.
 19. The supercooling method ofclaim 18, wherein the supercooling method performs a step of comparingthe upper sensed temperature and the lower sensed temperature with afirst upper reference temperature and a first lower referencetemperature, respectively, when the temperature of the lower portion ofthe storing space or the stored object is lower than a presettemperature-control start temperature, and performs the upper heatsupply step and the lower heat source supply step when the upper sensedtemperature and the lower sensed temperature are smaller than the firstupper reference temperature and the first lower reference temperature,respectively.
 20. The supercooling method of claim 19, wherein thesupercooling method performs a step of comparing the upper sensedtemperature and the lower sensed temperature with a second upperreference temperature and a second lower reference temperature,respectively, when the temperature of the lower portion of the storingspace or the stored object is lower than a preset temperature-controlstart temperature, and stops the operation of the upper heat sourcesupply step and the lower heat source supply step, respectively, whenthe upper sensed temperature and the lower sensed temperature are largerthan the second upper reference temperature and the second lowerreference temperature, respectively.
 21. The supercooling method ofclaim 20, wherein the supercooling method maintains the previousoperation of the upper heat source supply step and the lower heat sourcesupply step when the temperature of the lower portion of the storingspace or the stored object is lower than the preset temperature-controlstart temperature and when the upper sensed temperature and the lowersensed temperature exist between the first upper reference temperatureand the second upper reference temperature and between the first lowerreference temperature and the second lower reference temperature,respectively.
 22. The supercooling method of claim 17, comprising a stepof circulating the air in the lower portion of the storing space byforcible convection.
 23. The supercooling method of claim 22, whereinthe supercooling method performs the forcible convection step when thelower sensed temperature is higher than a forcible convection referencetemperature, and when the lower sensed temperature is equal to or lowerthan a forcible convection reference temperature, if either the upperheat source supply step or the lower heat source supply step isperformed, the supercooling method performs the forcible convectionstep.
 24. (canceled)